A smart meter network is a sensor network for facilitating public utility services, such as electricity, water, and gas. As shown in FIG. 1, a smart meter network includes smart meter sensors (M) 101, and data concentrators 102 that are connected 103 to control networks, typically via a wired link. Communication between the smart meters and the concentrators typically uses wireless links for data and control packets. The sensors and concentrators are generally termed “nodes.”
A smart meter network is distinguished from conventional sensor networks. The smart meter network can include thousands of smart meters, and only one or a few data concentrators. Both the smart meter and the concentrator are stationary, e.g., installed in homes and buildings. A smart meter periodically collects data and transmits the data via wireless links to one or more concentrators. The concentrators transmit the data to control networks of public utility service companies via wired links. The concentrator can transmit control commands to one or more smart meters. Data and control packets are reliably delivered to the concentrators and smart meters, respectively, with a low latency, such as a few seconds.
The smart meters and the concentrators form a large scale multi-hop mesh network, where packets may need to be relayed via other nodes. The manner in which the packets are relayed is critical. Therefore, reliable routes must be used.
A typical smart meter node M 101 can select concentrator C1 as its primary concentrator and concentrator C2 as a backup concentrator. Node 101 M has two routes to the primary concentrator and one route to the backup concentrator.
A number of routing methods are known for wireless sensor networks, and mobile ad hoc networks based on different requirements. Ad-hoc On-demand Distance Vector (AODV), Ad-hoc On-demand Multipath Distance Vector (AOMDV) and Dynamic Source Routing (DSR) are well known, However, those routing methods are not suitable for smart meter network because they are designed for homogeneous networks in which any node can be a source or destination. In addition, AODV is a single route method.
AOMDV tries to discover multiple disjoint routes between a source and a destination. However, the problem is that some node cannot discover the set of disjoint routes. As a result, AOMDV can only discover a single route for some nodes.
The main issue with DSR is that each packet includes route information, i.e., a node list. The node list increases the overhead in packet, especially when the route is long.
Furthermore, multiple network-wide broadcast floods to determine routes in those conventional routing methods make their communication overhead too high for large smart meter networks.
Routing Protocol for Low power and lossy network (RPL) is another routing method. RPL uses a directed acyclic graph (DAG) for route discovery. However, many important issues are left unresolved by RPL. For example, rank computation is not described for the RPL.
Therefore, it is desirable to develop a routing method for smart meter networks to deliver data packets and control packets reliably with very low latency.